Abstract: Li₂O is widely used in the chemical industry, atomic energy industry, metallurgy and other fields. Li₂CO₃ is the most common raw material for preparing Li₂O. The study on the thermal decomposition of Li₂CO₃ plays an important role in preparing Li₂O. This paper explored the thermal decomposition of Li₂CO₃under vacuum, the addition of alumina to promote the thermal decomposition of Li₂CO₃ at normal pressure and vacuum conditons, respectively. From the methods above, the detailed thermodynamic analysis provided relevant data for the thermal decomposition behavior of Li₂CO₃. Moreover, this paper introduced the current research status and development of the thermal decomposition of Li₂CO₃ worldwide. The advantages of vacuum preparation of Li₂O were noted for future research, which provides a reference for selecting Li₂O preparation processes.